Magnetic separator



- .Nov. 21 1923.

, 1,475,457 W. G. SWART M MAGNETIC SEPARATIOR Filed Aug. 18, 1922 5 Sheets-Shet 1- Nov. 27,1923. 1,475,457

' was. SWART MAGNETIC SEPARATOR Filed Aug 18. 1922 v is Sheets-Sheet 2 w m M QYMMQSM Nov. 27, 1923. 1,415,457

W. G. SWART MAGNETIC SEPARATOR Filed Aug. 18. 1922 3 SheetsSheet 5 x Qw XM' 'mkma Q M M,

Patented Nov. 27, W23.

UNHTE STATS.

WALTER G. SWART, 0F BABBIT'I', MINNESOTA.

MAGNETIC SEPARATOR.

Application filed August 18, 1922. Serial No. 582,785.

To all whom it may concern.

Be it known that I, WALTER G. SWAR'r, a citizen of the United States, and residing at Babbitt, county of St. Louis, and State of Minnesota, have invented certain new and useful Improvements in Magnetic Separators, of which the following is a specification.

This invention relates to magnetic separators and is designed primarily to overcome the diificulties heretofore encountered in separating the fine non-magnetic material from the magnetic material which is recovered thus greatly improving the quality of the magnetic product while at the same time more effectively andcompletely recovering the magnetic material including the very fine as well as the coarse material. Heretofore the so-called fines, which are always present in crushed ore due to grinding varying in degree according to the fineness of the grinding, have interfered with the production of a clean satisfactory magnetic concentrate since in the systems heretofore-used the treatment has not been sufiicien'tly effective to remove all of the fine non-magnetic particles from the magnetic particles and usually fine ground ore and coarse ground ore have been subjected to somewhat difierent treatments. A device embodying the present invention will satisfactorily treat either fine or coarse material or a mixture of the two. Although the fineness ot' grinding varies greatly with ores having diiierent characteristics, it may be stated, as a general rule, that it clean products are to be obtained by magnetic separation of material crushed liner, for instance, than 1/20 inch diameter, the material must be constantly and thoroughly agitated during its passage through the magnetic field in order to liberate the non-magnetic material and allow it to descend by gravity and the finer the crystallization and the finer the crushing the more thorough and prolonged must be the agitation. Since line grinding has become practical and common in recent years the importance and seriousness of the problem of successfully and satisfactorily separating the line non-magnetic particles from the magnetic particles and at the same time recovering the line magnetic particles have become much greater and have attracted more attention and caused great etl'orts to remedy the defect. It now seems to be definitely settled that fine material must be handled the lines of force instantly bind adjacent magnetic particles into masses trapping and entanghng non-magnetic particles in those masses and those non-metallic particles canngt escape and fall from the field unless the masses are broken and agitated and the part cles caused to change their relative posit1ons and it follows of course that the more thorough and prolonged the agitation is, the clearer will be the separation. Ore crushed comparatively coarse has been successfully separated by passing it across magnet poles which were alternately north "aiid south causing the coarse particles of magnetic material to turn over, thus agitating the masses and permitting the non-magnetic particles to drop therefrom. However the nature of this agitation taken with the limited time of its continuance prevented this system from satisfactorily separating the fine non-magnetic particles from the magnetic material. Although the well-known Grondal system has been applied with success to ore ground fine enough to pass through 20 meshes per linear inch it was usually necessary to use several machines in series in order to obtain clean concentrates and on very fine material the capacity is very low and the separation below the desired standard. A separator embodying means for mechanically agitating and moving the material being treated through the magnetic field has heretofore been designed and although the agitation of the material is more thorough and efiective while it lasts than it was in machines where the agitation was due to reversal of poles but the length of the field of treatment in this form as well as in the others has been limited and thus the operation could not continue long enough to permit all of the fine material to escape when ver fine material is being 0 erated on.

no great drawback there ore to the ade. quate and satisfactory separation of the magnetic material from the very fine nonmagnetic material has been the limited len rth ot' the field through which the material travels during the agitation and mag-. netic separating action and this prevented the sufficiently prolonged treatment to reinclined position to aligned p move all of the fine non-magnetic material. Another defect in the previously used separating means consisted in the fact that the water used was not applied in the best and most effective way during treatment to separate the fine non-magnetic material from the magnetic material. The present invention makes is possible to have a field of treat ment of any desired length within reason and thus to prolong the treatment to any extent desired for practical purposes and thus the length of the field may be made to correspond tothe requirements of the particular case. It also provides means by which there is a continuous unobstructed flowof Water downwardly entirely through the material being treated from above while it is being agitated mechanically and its collected masses of magnetic material are being broken up thus most efi'ectively washing out and separating the fine non-magnetic material from the magnetic material and carrying it downward out of the field. This continuous etlective mechanical stirring with the steady downflow of water through the material effectively washes out the fine non magnetic material if continued suii iciently 1on and causes a high grade concentrate. fine very important novel feature of the present invention resides in the means for creating between two upstanding parallel surfaces amagneticfield which isnarrow vertically but which has any desired honizontal length whereby the ore to be treated may be fed to the space between these surfaces from above and the magnetic content arrested by and retained in said field while water passes downward through it and the material in the field is being mechanically agitated and moved longitudinally of the field. The novel features of the invention will be more fully understood from the following description and claims taken with the accompanying drawin s. In the drawings;

igure 1, is a side view partly broken away and partly in vertical section of one embodiment of the invention;

Figure 2, is a cross section on the line 22 of Figure 1;

Figure 3 is a side view of a device similar to that shown in Figure 1 except that the pole shoes of the magnets, creating the field, are in inclined overlapped position;

Figure 1 is a similar view showing the magnets of still another form in which the pole shoes are arranged vertically, spaced equally apart longitudinally of the tank; Figure 5 is a side view of a form somewhat similar to that shown in Figure 3 but in this case the adjacent pole shoes are pivotally supported at their centers "from the okes so that they may be changed from an Figure 6 is'a view simiiar to Figure'Q a erage?- magnets forming a duplexsystem of tanks and separators side by side;

Figure 7 is a side view partly in vertical section of the discharge end of a dilieren't form of separator and conveyor from that shown in Figure 1;

Figure 8 is a section on the line 8-8 of Figure 7; and,

Figure 9 is a diagrammatic showing of one method of controlling the strength of the magnetic field.

As will be seen in Figures 1 and Q, the particular embodiment of the invention there shown for the purpose of illustration includes a narrow tank 10 mounted on suitable supports and which may be made of brass, copper, zinc, lead, wood or other nonmagnetic material such as is adapted to hold water and it can even be made of iron or steel if desired. As will be seen by reference to Figure 2 it has upstanding facing side walls 11 and 12 which are parallel and is open at the top. The bottom of this tank is so shaped as toform a series of successive chambers-or receptacles by the inclined bottom walls 13 and 14. meeting on a sharp edge 15 transversely of the tank so that any material falling from above will be divided on the line 15. These chambers are inclined to their lower ends and terminate in discharge spouts 16, 17, 18,19, 20, 21., 22 and these discharge spouts are of a well-known construction which permits drawing off the solid contents of these chambers as well as conveying water. upper outer edges gutters or troughs 23, 24 having open tops the inner wall of each consisting of the upper portion of the side wall or tank 10 and the outer wall of each extending upwardly above the inner wall. Water pipes 25 supply water to this trough and during operation the water level is maintained above the top edges of the side walls 11 and 12 of tank 10 but some water is always and constantly discharged at a lower level from the tank as from the spig ots 16 and 17 etc., so that there is a constant dovvnflow of water from the tank.

A magnetic field is created across the upper portion of the tank 10 between the walls 11 and 12 just below the side troughs 23 and this magnetic field may be produced invarious ways but it should be relatively narrow in a vertical direction and elongated in a horizontal direction to the length which is desired since in operation the material being treated is moved longitudinally of the field suspended between the walls Ill and 12 by magnetic attraction for the magnetic particles. lln the form shown in Figure 1, there are a series of iron or steel cores or yokes 26, 2?, 28, and and on each yoke there is a magnetic ceil or winding Bl of insulated wire and the nature of the winding. for the but showing merely the tank and electrm [Sill The tank 10 has at its 7 difierent winding yokes may be made to correspond with the character of the results desired as is well-known in the art.

The magnet yokes terminate in pole shoes 32, 33 which in vertical section haveV- shaped edges close to the outer surface of the walls of tank 10 as will be seen by ref: erence to Figure 2. In the form shown'in Figures 1 and 2 these pole shoes are in line and are preferably made in one integral pole or shoe extending the full length having a magnet yoke at intervals to energize its succeeding sections.

The ground ore to be treated may be fed in any suitable way but must be fed from above so as to pass downwardly into the magnetic field produced between the walls 11 and 12 and as shown in Figures 1 and 2 this may be done by a spout 34. The magnetic field between the pole shoes 32 and 33 is very intense and when the crushed ore is supplied to the space from above and passes downward the magnetic particles are arrested by the magnetic field and prevented from falling further making contact with the side walls of the tank until a more or less solid mass is formed between the two sides of the tank. In addition to stopping the magnetic particles many non-magnetic particles will necessarily be caught with the magnetic and entangled in the masses and will not be free to escape and fall by gravity. It would be very'difiicult to' move the collected masses including the magnetic material up or down out of the magnetic field since the fieldis so strong, but they can be moved horizontally still in the field with comparative ease and thus they can be mechanically stirred and moved horizontally, thus releasing nonmagnetic material which has been enclosed or entrapped by it. Any suitable means may, of course, be used to agitate or move theimasses of material collecting in the magnetic field from the inlet end to the other end and it may be moved by a continuous pushing action or intermittent reciprocating action, which, however, should operate continuously. In the form shown in Figures 1 and 2, the means for stirring and moving the masses of material along the magnetic field consists of an endless belt 35 mounted on pulley wheels 36, 37 which are driven from any suitable source of power. Mounted on the belt 35, there are blades or scrapers 38 preferably arranged in transverse rows as shown in igure 2 and at short intervals longitudinally and this belt being mounted parallel to and just above the tank 10. The arms or scrapers 38 extend downwardly into the tank from the lower section of the belt and extend entirely across the magnetic field created by the pole shoes 32 and 33 so that they will in moving in the direction indicated by the arrow, gradually move the masses of material collected longitudinally of the field to the end 39. At that point the remaining material will be only magnetic which when pushed beyond the field will dro bygravity into the-chamber 40 im me iately below it. It will be understood that the non-ma netic material will drop from the magnetic field from the point of supply at spout 34 along the diflerent stages of its passage with the magnetic material be observed that the constant stirring of the masses in the magnetic field moving it forward steadily and the washing action of the water passing constantly downward through the material during its agitation will thoroughly remove the non-magnetic material no matter how fine it is, if the field is made long enough. In this apparatus, the size of the particles being treated has little or no effect on the separation since all ma etic particles of any size are firmly held inthe field between the poles and all non-magnetic particles fall through to the discharge hoppers either by gravity, if they are coarse, or by the washing action of the water if they are fine.

In order to have a practically continuous magnetic field, which is narrow vertically, of any desired length horizontally, it is not necessary that the pole shoes on the opposite sides shall be in one single piece of metal energized atintervals but they may consist of separate pole pieces for each magnet, elongated horizontally and close together end to end or they may be arranged as shown in Figure 3 where the pole shoes 41 are shown mounted on the ends of the yoke 42 at an angle to the horizontal with successive. pole shoes at a similar angle each pole shoe partly overlapping the end of the adjacent pole shoe on each sideof the tank. In this form, as will be seen, the magnetic material collected in masses will, by the raking and scraping action from the right to the left in the drawing, move up the inclined field section produced by one pair of pole shoes and will then drop to the similar inclined field section produced by the next pair of pole shoes and so on to the end. It will, of course, be obvious that this arrangement of the pole shoes could be used to form part of the magalong the field when it becomes exposed and I top.

netic field in the arrangement shown in Figure 1 such as the discharge end.

In Figure 4:, another arrangement is shown for making a relatively narrow magnetic field in a vertical direction and making it practically continuous in a longitudinal direction for any distance desired. Tn this instance, the magnet yokes 43, having their windings td, are divided at their upper ends forming two parallel vertical pole shoes 45, 46 on opposite sides of the tank 10 near the The pole shoes on each side of the tank are placed near enough together in succession to cause lines of force to cross the tank at all points longitudinally of the upper zone from the shoe at one end of the series to the shoe at the other end but they may not be so intense and effective midway between adjacent pole shoes as at the shoes and thus, although the magnetic field is continuous and has sufficient strength at all points for prac' tical use, it may not always be exactly uniform and therefore the arrangement of pole shoes shown in Figs. 1 and 2 is considered preferable.

In Fig. 5, still another modification of the pole shoe arrangement is shown. lin this case each elongated polo shoe 4'? has the V- shaped edge facing the tank, as shown in Fig. 2. but has tapered ends and is pivotally connected at its center to the upper end of a magnet yoke arm at as whereby it may occupy the inclined position shown in full lines or the horizontal position shown in dotted lines in Figure 5. lVhen the series of shoes are in inclined full line position, the magnetic field generated corresponds in a sense to that of the arrangement shown in Figure 3 and the magnetic material moved by the scrapers passes at an upward incline in the section of the field formed by each pair of opposite pole shoes and passing off the upper end of that section falls to the section of the field created by the next pair of shoes. In this instance the adjacent pairs of shoes do not overlap as in Fig. 3. but the magnetic fields created by adjacent sets do overlap and thus the magnetic material is delivered from one section to the next. Tn the arrangement shown in dotted lines in Fig. 5, the magnetic field is straight and continuous as in Fig. 1.

Fig. 6 shows a multiple arrangement of separators with pole shoe arrangement corresponding to that of Figs. 1 and 2 in which there are three tanks 49, 50 and 51 side by side. The magnetic fields across the upper portions of these tanks may be produced by a series of four pronged magnet yokes 52, energized in any suitable way, as by the three coil windings 52, 54 and 55, each prong being connected at its upper end to a horizontally extending pole shoe having a V- shaped edge close to the outer surface of the retrace? adjacent tank at its upper end; The pole shoes on the prongs between the tanks have oppositely facing V-shaped edges closely adjacent the Walls of the tanks. The means for supplying water and ore and for agitating and movingthe masses containing magnetic material which collect in the magnetic fields in the tanks are not shown in this figure but it will be understood that they are necessary in the operation of the device and may be of the kind shown in Figs. 1 and 2.

In Figure 7, the broad features of the invention are shown embodied in a magnetic has the side troughs and 61 corresponding to those shown in Figure 1 and water is constantly supplied to these troughs and overflows into tank 56 maintaining the water level at the top of the walls of the tank 56. The rotary shaft 62 is mounted longitudinally of the tank 56 and has connected to it by spokes G3 a spiral conveyor 64 which moves close to the inner surfaces of the walls of the tank 56 at its bottom and at the opening 57. The magnet yokcs 65 are connected at intervals to pole shoes 60 and 67 which fit the lower surface of the tank 56 on the outer sides down to the bottom opening 57 and these pole shoes are energized by the coil windings 68 on the yokes 65. The ground ore to be treated is fed to the tank 56 and the conveyor 64; at the end of the machine which is broken away in Figure '4' and in this respect is the same as in the Davis patent above mentioned.

There is of course a strong nmgnctic field throughout the bottom portion of the tank 56 in contact with pole shoes 66 and 67 and across the bottom opening 57 and the magnetic material fed to the tank above one end of that field will be arrested by'it and prevented from descending by gravity down the laterally inclined surfaces to and through said central opening 57. Non-magnetic material, however, which happens to be free and not entangled with magnetic material when it reaches the opening 57 may fall through by gravity into supplemental tank 58 and be carried longitudinally of that tank by screw conveyor 59 to thedischarge chute 70. The magnetic material arrested in the llt) magnetic field in tank 56 adjacent said opening 57 will tend to collect in masses and the current flowing through its coil.

names? terial but the spiral conveyor 64 by its constant movement will strike and break such masses and move them longitudinally of the tank thoroughly agitating the material and giving the non-magnetic particles ample chance to escape through bottom opening 57. The opening or slot 57 preferably terminates at the discharge end of the separator as shown in Figure 7 some distance from theend of tank 56 and also from the ends of the pole shoes 66 and 67. The magnetic material is carried beyond the end of this opening by the spiral conveyor 64 and discharged into chute 69 which leads to a collecting receptecle not shown. The non-magnetic material passing through opening 57 into supplemental chamber 58 at different points throughout its length is engaged by the screw conveyor 59 and moved along that chamber to and discharged into discharge chute 70.

It will of course be understood that the rate of downward flow of water through the material in the magnetic field during treatment may vary in accordance with the character or condition of the ore or as circumstances require. It will also be understood that the relative intensity or strength of the magnetic field at different points longitudinally may be made to vary in predetermined ways to secure different desired effects or results such for instance as male ing the magnetic field near the feed end very strong by the known means of bring-- ing the pole shoes nearer together, sharpening them, using more wire or more current and gradually decreasing the intensity or strength of the successive field sections to the discharge whereby it is possible to recover very clean high grade concentrate from the last discharge spout of the series, a slightly less high grade product from the next spout and very clean tailings from the first two spouts. -One arrangement for controlling the intensity of the field at various points is shown schematically in Fig. 9. The magnet coils 31, corresponding to those in Fig. 1, may be of identical construction, and are connected in parallel across a constant voltage source of direct current G. Each coil is connected in series with a' rheostat R, which may be regulated to control The strength of the field produced by each coil is proportioned to the ampere turns of that coil, and if the coils are of identical constructon, the variation in field strength will be inversely proportioned to the resistance introduced by the rheostat R. It is not necessary that the surfaces between which the magnetic field is created shall be vertical since they may be at any angle to a vertical plane which will permit unrestrained material to freely pass downwardly between and in contact with them, one specific form illustrating this being shown in Fig. 8, and

it will be further understood that in any arrangement where the facing surfaces of the opposite pole shoes are of suflicient width vertically and at the proper angle to the vertical as in the form shown in Fig. 8 they may in and of themselves form the exposed surfaces between which the material is treated without interposing the thin walls of the tank between them. Although in the forms shown for purposes of illustration the corresponding longitudinal lines of the two surfaces between which the magnetic field is produced are straight and parallel for convenience and simplicity this straight parallel line. arrangement is not necessary but it is necessary for the most effective operation that corresponding portions of the two surfaces be spaced apart horizontally with substantial uniformity throughout their length leaving an opening for the downward passage of material out of the field of substantially uniform width.

Although various specific embodiments of the invention are shown, it is not limited to the details beyond what is indicated in the following claims.

What I claim aS new and desire to secure by Letters Patent is:

1. A magnetic separator comprising in combination two horizontally elongated surfaces spaced a short distance apart horizontally, means for creating a magnetic field with its lines crossing the space between said surfaces from opposite sides, means fo supplying crushed ore to the space between said surfaces above said magnetic field .and means for mechanically stirring magnetic material suspended in said field and moving it along said surfaces in said field horizontally to the end and out of said field and means for caus ng water to flow downwardly through said field between said surfaces.

2. A magnetic separator comprising in combination two surfaces spaced a short substantially uniform distance apart horizontally, means for creating a magnetic'field between said surfaces of materially greater lengththan vertical width, means for feeding crushed ore downwardly between said surfaces into said field, mechanical means for breaking, stirring, and moving longitudinally of said field the masses of crushed ore containing magnetic material suspended in said field and means for causing water to simultaneously pass downwardly through said field between said urfaces whereby the materially greater length than vertical width, means for feeding crushed ore downwardly between said surfaces into said field, means for mechanically breaking, stirring, and moving longitudinally of said field the masses of crushed ore containin magnetlc -material suspended in said field t ereby pera magnetic field between said surfaces ofrnaterially greater length than vertical width, means for feeding crushed ore downwa'rdly between said surfaces into said field, means for mechanically breaking, stirring, and moving longitudinally of said field the masses of crushed ore containing magnetic material suspended in said field, means for causing water to flow downwardly through said field between said surfaces thus causing the freed non-magnetic particles to move downwardly from said field, means below said field for separately receiving and collecting material descending from predetermined successive sections'of; said field, the the said means for creatin said magnetic field consisting of a series of electromagnets in succession with cooperating pole shoes creating the successive sections of said magnetic field.

5. A; magnetic separator comprising in combination two facing elongated surfaces of predetermined length in a horizontal direction spaced a short distance apart horizontally, means for creating a magnetic field at and between said surfaces of predetermined length, and of smaller vertical width, the said surfaces being so arranged with reference to vertical lines that unrestrained material in contact with them will fall or slide downwardly between them out of the field by gravity, means for feeding crushed ore to the space between said surfaces above said'field and means for mechanically stirring masses of ore containingmagnetic material suspended in said field and moving it in a horizontal direction along said surfaces in said field to its end and means for causing a flow of water downwardly through said field between said surfaces.

6. A. magnetic separator comprising in combination two elongated fixed wall surfaces spaced apart horizontally a short uniform distance, electromagnetic means operating from the outer sides of said wall sur faces for creating a longitudinally extendin vertically narrow continuous magnetic field between said surfaces for-a predetermined distance, means for causing water to contin- Leases? uously flow downward between and in contact with said surfaces, means for supplying crushed ore to the space between said wall surfaces above one end of said magnetic field and mechanical means operatingcontinuously for breaking and agitating the masses of magnetic material which collect in said magnetic field and for simultaneously moving it along that field from the point ofsupply to its end.

7. A magnetic separator comprising in combination a narrow tank having horizontally spaced side wall surfaces, means for creating a vertically narrow but longitudinally continuous magnetic field between said surfaces materially above the bottom of said tank, means for maintaining a water level in said tank above said magnetic field and for causing a continuous flow of water down through said field in said tank, means for supplying crushed ore to said tank near one end of said magnetic field, and mechanical means operating continuously for agitating and stirring the magnetic material suspended in the magnetic field and for gradually moving it along said field from the point of glupgly to and beyond the other end of said 8. A magnetic separator comprising in combination a narrow elongated tank having longitudinally uniformly spaced side wall surfaces, means for creating a vertically narrow but longitudinally continuous ma netic field between said surfaces material y above the bottom of said tank, means for causing a. continuous flow of water down through said field in said tank, means for supplying crushed ore to said tank near one end of said magnetic field, mechanical means operating continuously for agitatingand stirring the magnetic material suspended in the magnetic field and for gradually moving it along said field from the point of supply to and beyond the other end of said field, a series of separate but longitudinally adjacent collecting chambers along the bot tom of said tank below said magnetic field from the supply end to and beyond the discharge end for separately collecting solid material falling from said field.

9. A magnetic separator comprising in combination a narrow elongated tank having longitudinally uniformly spaced side wall surfaces, means for creating a vertically narrow but longitudinally continuous magnetic field between said surfaces materially above the bottom of said tank, means for causing a continuous flow of water down through said field in said tank, means for sup-plying crushed ore to said tank near one end of said magnetic field, mechanical means operating continuously for agitating and stirring the magnetic material suspended in the magnetic field and for gradually moving it along said field from the point of supp-1y to and beyond the other end of said field, a plurality of collecting chambers extending across said tank at its bottom in succession 10. A magnetic separator comprising in combination a narrow elongated tank hav ing side wall surfaces uniformly spaced horizontally, means for creating a vertically narrow but longitudinally continuous magnetic field between said surfaces. materially above the bottom of said tank, means for maintaining a water level in said tank above said magnetic field and for causing a continuous flow of water down through said field in said tank, means for supply ing crushed ore to said tank near one end of said magnetic field, mechanical means operating continuously for agitating and stirring the magnetic material suspended in the magnetic field and for gradually moving it along said field from the point of supply to and beyond the other end of said field, a series'of downwardly tapering collecting chambers having discharge spouts for material falling by gravity at the bottom of said tank below said magnetic field and a .downwardly. tapering collecting chamber having a discharge spout for magnetic material below the end of said field.

11. A magnetic separator comprising in combination a narrow elongated tank having side wall surfaces uniformily spaced horizontally, means for creating a vertically narrow but longitudinally continuous mag netic field between said surfaces materially above the bottom of said tank, means for maintaining a water supply to said tank above said magnetic field and for causing a continuous flow of water down through said field in said tank, means for supplying crushed ore to said tank near one end 0 said magnetic field, an endless conveyer extending longitudinally of said tank above, and extending beyond the ends of said mag netic field having attached thereto at intervals a series of blade like scrapers extending downwardly into said tank across said magnetic field, means for continuously operating said conveyor whereby said blades will agitate the n'iagnetic material suspended in said magnetic field and move it from the point of suppl to and beyond the end of said field and a c iamber in said tank below the end of the field for receiving the magnetic material.

12. A magnetic separator comprising in combination a narrow elongated tank ham ing fixed side walls spaced a unit irm distance apart horizontally at all points longs tudinally, a series of magnet yokes with f 'field between said central windings at intervals along said tank the said yokes terminating at elongated pole pieces close to the outer sides of said walls forminga continuous magnetic field between them across the upper portion of said tank, means for maintaining a water level'in said tank above said field and for causin a continuous fiow of water down throug said field, means for supplying crushed ore to said tank near one end of said field and continuously operating mechanical means for agitating and stirring the magnetic material suspended in said magnetic field and gradually moving it along said field from the point of supply to and beyond the other end of said field.

13. A magnetic separator comprising in combination a narrow elongated tank having fixed uniformly spaced side walls, a series of magnet-yokes with central Windings at intervals along said tank, the said yokes terminating in elongated pole pieces having facing surfaces V-shaped in vertical section close to the outer sides of said Walls forming a continuous magnetig field between them across the upper portion of said tank, means for causing a continuous flow of water down through said field, means for supplying crushed ore to said tank near one end of said field and continuously operating mechanical means for agitating and stirring the magnetic material suspended in said magnetic field and gradually moving it along said field from the point of supply to and begond the other end of said field.

14. magnetic separator comprising in combination a narrow elongated tank having fixed side walls, a pair of narrow elongated integral pole pieces extending longitudinally of said tank near the surfaces of its side walls near the top of the tank and magnet yokes having central windings operatively connected at their ends to said pole pieces at interval longitudinally of said tank thus producing a continuous magnetic Sole pieces across the upper portion of sai tank, means for causing a continuous flow of water down through said field, means for supplying crushed ore to said tank near one end of said field and continuously operating mechanical means for agitating and stirring the magnetic material suspended in sald magnetic field and gradually moving it across the upper portion of said tank, means for maintaining a water level in said tank above said field and for causing a continuous flow of water down through said field, means for supplying crushed ore to said tank near one end of said field and continuously operating mechanical means for agitating and stirring the magnetic material sus= pended in said magnetic field and gradually moving it along said field from the po1nt of supply to and beyond the other end of said field and means along the bottom of said tank fordividing and separately collecting and discharging solid materia falling from predetermined longitudinal sec tions of said magnetic field whereby such material may be classified.

16. A magnetic separator comprising in combination two facing elongated surfaces along said surfaces in said field to its end,

and means for causing a continuous downward flow of water between said surfaces.

17. A magnetic separator comprisin in combination two facing elongated surt aces of predetermined length in a horizontal direction spaced a short distance apart horizontally, means for creating a magnetic field'at and between said surfaces of predetermined length, and of smaller vertical width, the said surfaces being so arranged with reference with vertical lines that unrestrained material in contact with them will fall or slide downwardly between them out of the field by gravity, means for controlling the strength of predetermined longitudinal sections of said field, means for feeding crushed ,ore to the space between said surtacesabove said field near one end and means for mechanically stirring masses of ore containing magnetic material suspended in said field and moving it in a horizontal direction along said surfaces in said field to its end and means below said field for separately collecting material talling from different predetermined longitudinal sections of said field.

18. A magnetic separator comprising in combination a ,narrow elongated tank having fixed side walls, longitudinally arranged pole piems opposite each other close to the manner sides of said walls above the bottom of the tank, means at intervals along aid tank for energizing said pole pieces to a predetermined degree forming a magnetic field across the upper portion of said tank, means for causing a continuous flow of water down through said field, means for supplying crushed ore to said tank near one end of said field and continuously operating mechanical means for agitating and stirring the magnetic material suspended in said magnetic field and gradually moving it along said field from the point of supplyto and beyond the other end of said field, and means along the bottom of said tank for dividing and separately collecting and discharging solid material falling from predetermined longitudinal sections of said field whereby such material will be classified.

19. A magnetic separator including in combination two thin walls spaced a uniform? distance apart, horizontally elongated pole shoes opposite each other onthe outer sides of and close to aid walls ll-shaped in cross section with the points of the V- shape facing each other and means for energizing said pole pieces, andv means for passing water downwardly between said Walls. v

20. A magnetic separator including in combination two thin walls spaced a uniform distance apart, horizontally elongated pole shoes opposite each other on the outer sides of and close to said walls V-shaped in in cross section with the points of the V- shape facing each other and a magnet yoke with a central winding connected at its ends to said pole shoes for energizing them, and means for passing water downwardly between saidvwa-lls.

21, A magnetic separator comprising a pair ct elongated pole shoes of an electromagnet spaced apart horizontally a uniform distance with a vertical opening between them, mean for passing crushed ore and water by the action of gravity downwardly in said opening between them and means for mechanically'stirring and longitudinally moving the masses of material containing magnetic matter collected and suspended in the magnetic field between said pole shoes. g

22.. A magnetic separator comprising combination two horizontally elongat surfaces spaced a short distance apart ho. aontally, means for creating a magnet field with itslines crossing the space i; a tween said surfaces from opposite s means for supplying crushed ore to t space between said surfaces above said ma, neticv field and means movin longitudinal of said field for mechanicalgy stirring mag netic matter suspended in said field and. moving it along said surfacesin said field lid horizontally to the end and out of said fieldv 23. A magnetic separator comprising in combination two stationary surfaces spaced a short distance apart horizontally, means for creating a magnetic field between said surfaces of materially greater length than vertical width means for feeding crushed ore downwardly between said surfaces into said field, means for mechanically breaking, stirring, and moving longitudinally of said field the masses of crushed ore containin magnetic material suspended in said field thus permitting the freed non-magnetic articles to move downwardly from said eld by gravity, means below said field for separately receiving and collecting non-magnetic material descending from redetermined successive sections of said eld, the said means for creating said magnetic field consisting of a series of electromagne'ts in succession with cooperating pole shoes creatkng the successive sections ofsaid magnetic eld.

24. A magnetic separator comprisin in combination two facmg elongated sur aces of predetermined length in a horizontal direction spaced a short distance apart horizontally, means for creating a ma etic field at and between said surfaces 0 predetermined length, and of smaller vertical width, the said surfaces being so arranged with reference to vertical lines that unrestrained material in contact with them will fall or slide downwardly between them out of the field by gravity, means for feeding crushed ore to the space between said surfaces above said field and means independent of said surfaces for mechanically stlrrin masses of ore containing magnetic materia suspended in said field-and movin it in a horizontal direction along said sur aces in said field to its end.

25. A magnetic separator comprising in combination two facing elongated stationary slirfaces of predetermined length in a horizontal direction spaced a short distance apart horizontally, means for creating a magnetic field at and between said surfaces of predetermined length, and of smaller vertical width, the said surfaces being so arranged with reference to vertical lines that unrestrained material in contact with them will fall or slide downwardly between them out of the field by gravity, means for feeding crushed ore to the space between said surfaces above said field near one end and means for mechanically stirring masses of ore containing magnetic material suspended in said field and movin it in a horizontal direction along said sur aces in said field to its end and means below' said field for separately collecting material falling from different redetermined longitudinal sections of said eld,

26. A magnetic separator including in combination, horizontally elongated pole shoes op osite each other horizontally and suflicient y close to each other to create a strong magnetic field between them, means for freely passing crushed ore downwardly between them through said field, mechanical means movable longitudinally of the field for engaging, agitating and stirring masses of magnetic material suspended in said field and moving it along said field to its end while perm1tting non-magnetic material to fall therefrom by gravity.

27. A magnetic separator including in combination, horizontally elongated pole shoes op osite each other horizontally and suflicient y close to each other to create a strong magnetic field between them, means for freely passing crushed ore downwardly between them through said field, mechanical means movable longitudinally of the field for engaging, agitating and stirring masses of magnetic material suspended in said field and moving it along said field to its end while perm1tting non-magnetic material to fall therefrom by gravity, and means for causing water to pass downwardly through the material in said field during said agif tation and movement.

In testimony whereof I hereunto aflix my signature.

WALTER G. SWART. 

